You might have had a bit of a shock on attempting to launch iPhoto on an iPhone or iPad after upgrading to iOS 8. The app was abruptly dead and inaccessible, superseded by Photos, which gained filters and more editing capabilities. In 2015, Apple will bring similar thinking to the Mac, replacing iPhoto with an OS X version of Photos.
Generally, when a desktop app is retired, it doesn’t suddenly stop working and force you to migrate to an alternative product. Chances are, you’ll still be able to continue using iPhoto for a while – although that’s not guaranteed. However, it’s clear that if you’re an iPhoto user on OS X Yosemite, you should start planning ahead, because Apple’s made it clear iPhoto has no future.